An interest rate is de amount of interest due per period, as a proportion of de amount went, deposited or borrowed (cawwed de principaw sum). The totaw interest on an amount went or borrowed depends on de principaw sum, de interest rate, de compounding freqwency, and de wengf of time over which it is went, deposited or borrowed.

It is defined as de proportion of an amount woaned which a wender charges as interest to de borrower, normawwy expressed as an annuaw percentage.[1] It is de rate a bank or oder wender charges to borrow its money, or de rate a bank pays its savers for keeping money in an account.[2]

Annuaw interest rate is de rate over a period of one year. Oder interest rates appwy over different periods, such as a monf or a day, but dey are usuawwy annuawised.

For an interest-bearing security, coupon rate is de ratio of de annuaw coupon amount (de coupon paid per year) per unit of par vawue, whereas current yiewd is de ratio of de annuaw coupon divided by its current market price. Yiewd to maturity is a bond's expected internaw rate of return, assuming it wiww be hewd to maturity, dat is, de discount rate which eqwates aww remaining cash fwows to de investor (aww remaining coupons and repayment of de par vawue at maturity) wif de current market price.

Germany experienced deposit interest rates from 14% in 1969 down to awmost 2% in 2003

In de past two centuries, interest rates have been variouswy set eider by nationaw governments or centraw banks. For exampwe, de Federaw Reserve federaw funds rate in de United States has varied between about 0.25% to 19% from 1954 to 2008, whiwe de Bank of Engwand base rate varied between 0.5% and 15% from 1989 to 2009,[8][9] and Germany experienced rates cwose to 90% in de 1920s down to about 2% in de 2000s.[10][11] During an attempt to tackwe spirawing hyperinfwation in 2007, de Centraw Bank of Zimbabwe increased interest rates for borrowing to 800%.[12]

The interest rates on prime credits in de wate 1970s and earwy 1980s were far higher dan had been recorded – higher dan previous US peaks since 1800, dan British peaks since 1700, or dan Dutch peaks since 1600; "since modern capitaw markets came into existence, dere have never been such high wong-term rates" as in dis period.[13]

Possibwy before modern capitaw markets, dere have been some accounts dat savings deposits couwd achieve an annuaw return of at weast 25% and up to as high as 50%. (Wiwwiam Ewwis and Richard Dawes, "Lessons on de Phenomenon of Industriaw Life... ", 1857, p III–IV)

Powiticaw short-term gain: Lowering interest rates can give de economy a short-run boost. Under normaw conditions, most economists dink a cut in interest rates wiww onwy give a short term gain in economic activity dat wiww soon be offset by infwation, uh-hah-hah-hah. The qwick boost can infwuence ewections. Most economists advocate independent centraw banks to wimit de infwuence of powitics on interest rates.

Deferred consumption: When money is woaned de wender deways spending de money on consumption goods. Since according to time preference deory peopwe prefer goods now to goods water, in a free market dere wiww be a positive interest rate.

Infwationary expectations: Most economies generawwy exhibit infwation, meaning a given amount of money buys fewer goods in de future dan it wiww now. The borrower needs to compensate de wender for dis.

Awternative investments: The wender has a choice between using his money in different investments. If he chooses one, he forgoes de returns from aww de oders. Different investments effectivewy compete for funds.

Risks of investment: There is awways a risk dat de borrower wiww go bankrupt, abscond, die, or oderwise defauwt on de woan, uh-hah-hah-hah. This means dat a wender generawwy charges a risk premium to ensure dat, across his investments, he is compensated for dose dat faiw.

Liqwidity preference: Peopwe prefer to have deir resources avaiwabwe in a form dat can immediatewy be exchanged, rader dan a form dat takes time to reawize.

Taxes: Because some of de gains from interest may be subject to taxes, de wender may insist on a higher rate to make up for dis woss.

Banks: Banks can tend to change de interest rate to eider swow down or speed up economy growf. This invowves eider raising interest rates to swow de economy down, or wowering interest rates to promote economic growf.[14]

Economy: Interest rates can fwuctuate according to de status of de economy. It wiww generawwy be found dat if de economy is strong den de interest rates wiww be high, if de economy is weak de interest rates wiww be wow.

"Customs, juristic tradition, etc., have as much to do wif determining de average rate of interest as competition itsewf, in so far as it exists not merewy as an average, but rader as actuaw magnitude. In many waw disputes, where interest has to be cawcuwated, an average rate of interest has to be assumed as de wegaw rate. If we inqwire furder as to why de wimits of a mean rate of interest cannot be deduced from generaw waws, we find de answer wies simpwy in de nature of interest."[15]

For exampwe, suppose someone deposits $100 wif a bank for 1 year, and dey receive interest of $10 (before tax), so at de end of de year, deir bawance is $110 (before tax). In dis case, regardwess of de rate of infwation, de nominaw interest rate is 10% per annum (before tax).

According to de deory of rationaw expectations, borrowers and wenders form an expectation of infwation in de future. The acceptabwe nominaw interest rate at which dey are wiwwing and abwe to borrow or wend incwudes de reaw interest rate dey reqwire to receive, or are wiwwing and abwe to pay, pwus de rate of infwation dey expect.

The additionaw return above de risk-free nominaw interest rate which is expected from a risky investment is de risk premium. The risk premium an investor reqwires on an investment depends on de risk preferences of de investor. Evidence suggests dat most wenders are risk-averse.[16]

A maturity risk premium appwied to a wonger-term investment refwects a higher perceived risk of defauwt.

Most investors prefer deir money to be in cash dan in wess fungibwe investments. Cash is on hand to be spent immediatewy if de need arises, but some investments reqwire time or effort to transfer into spendabwe form. This is known as wiqwidity preference. A 1-year woan, for instance, is very wiqwid compared to a 10-year woan, uh-hah-hah-hah. A 10-year US Treasury bond, however, is wiqwid because it can easiwy be sowd on de market.

The spread of interest rates is de wending rate minus de deposit rate.[17] This spread covers operating costs for banks providing woans and deposits. A negative spread is where a deposit rate is higher dan de wending rate.[18]

The ewasticity of substitution (fuww name is de marginaw rate of substitution of de rewative awwocation) affects de reaw interest rate. The warger de magnitude of de ewasticity of substitution, de more de exchange, and de wower de reaw interest rate.

Higher interest rates increase de cost of borrowing which can reduce investment and output and increase unempwoyment. Expanding businesses, especiawwy entrepreneurs tend to be net debtors. However, de Austrian Schoow of Economics sees higher rates as weading to greater investment in order to earn de interest to pay its creditors. Higher rates encourage more saving and reduce infwation, uh-hah-hah-hah.

The effective federaw funds rate in de US charted over more dan hawf a century

The Federaw Reserve (often referred to as 'The Fed') impwements monetary powicy wargewy by targeting de federaw funds rate. This is de rate dat banks charge each oder for overnight woans of federaw funds, which are de reserves hewd by banks at de Fed.
Open market operations are one toow widin monetary powicy impwemented by de Federaw Reserve to steer short-term interest rates using de power to buy and seww treasury securities.

Financiaw economists such as Worwd Pensions Counciw (WPC) researchers have argued dat durabwy wow interest rates in most G20 countries wiww have an adverse impact on de funding positions of pension funds as “widout returns dat outstrip infwation, pension investors face de reaw vawue of deir savings decwining rader dan ratcheting up over de next few years” [19]

From 1982 untiw 2012, most Western economies experienced a period of wow infwation combined wif rewativewy high returns on investments across aww asset cwasses incwuding government bonds. This brought a certain sense of compwacency amongst some pension actuariaw consuwtants and reguwators, making it seem reasonabwe to use optimistic economic assumptions to cawcuwate de present vawue of future pension wiabiwities.

This potentiawwy wong-wasting cowwapse in returns on government bonds is taking pwace against de backdrop of a protracted faww in returns for oder core-assets such as bwue chip stocks, and, more importantwy, a siwent demographic shock. Factoring in de corresponding "wongevity risk", pension premiums couwd be raised significantwy whiwe disposabwe incomes stagnate and empwoyees work wonger years before retiring.[19]

Nominaw interest rates are normawwy positive, but not awways. In contrast, reaw interest rates can be negative, when nominaw interest rates are bewow infwation, uh-hah-hah-hah. When dis is done via government powicy (for exampwe, via reserve reqwirements), dis is deemed financiaw repression, and was practiced by countries such as de United States and United Kingdom fowwowing Worwd War II (from 1945) untiw de wate 1970s or earwy 1980s (during and fowwowing de Post–Worwd War II economic expansion).[20][21] In de wate 1970s, United States Treasury securities wif negative reaw interest rates were deemed certificates of confiscation.[22]

Negative interest rates have been proposed in de past, notabwy in de wate 19f century by Siwvio Geseww.[24] A negative interest rate can be described (as by Geseww) as a "tax on howding money"; he proposed it as de Freigewd (free money) component of his Freiwirtschaft (free economy) system. To prevent peopwe from howding cash (and dus earning 0%), Geseww suggested issuing money for a wimited duration, after which it must be exchanged for new biwws; attempts to howd money dus resuwt in it expiring and becoming wordwess. Awong simiwar wines, John Maynard Keynes approvingwy cited de idea of a carrying tax on money,[24] (1936, The Generaw Theory of Empwoyment, Interest and Money) but dismissed it due to administrative difficuwties.[25] More recentwy, a carry tax on currency was proposed by a Federaw Reserve empwoyee (Marvin Goodfriend) in 1999, to be impwemented via magnetic strips on biwws, deducting de carry tax upon deposit, de tax being based on how wong de biww had been hewd.[25]

It has been proposed dat a negative interest rate can in principwe be wevied on existing paper currency via a seriaw number wottery, such as randomwy choosing a number 0 drough 9 and decwaring dat notes whose seriaw number end in dat digit are wordwess, yiewding an average 10% woss of paper cash howdings to hoarders; a drawn two-digit number couwd match de wast two digits on de note for a 1% woss. This was proposed by an anonymous student of Greg Mankiw,[24] dough more as a dought experiment dan a genuine proposaw.[26]

A much simpwer medod to achieve negative reaw interest rates and provide a disincentive to howding cash, is for governments to encourage miwdwy infwationary monetary powicy; indeed, dis is what Keynes recommended back in 1936.

Bof de European Centraw Bank starting in 2014 and de Bank of Japan starting in earwy 2016 pursued de powicy on top of deir earwier and continuing qwantitative easing powicies. The watter's powicy was said at its inception to be trying to 'change Japan’s “defwationary mindset.”' In 2016 Sweden, Denmark and Switzerwand—not directwy participants in de Euro currency zone—awso had NIRPs in pwace.[27]

Countries such as Sweden and Denmark have set negative interest on reserves—dat is to say, dey have charged interest on reserves.[28][29][30][31]

In Juwy 2009, Sweden's centraw bank, de Riksbank, set its powicy repo rate, de interest rate on its one-week deposit faciwity, at 0.25%, at de same time as setting its overnight deposit rate at −0.25%.[32] The existence of de negative overnight deposit rate was a technicaw conseqwence of de fact dat overnight deposit rates are generawwy set at 0.5% bewow or 0.75% bewow de powicy rate.[32][33] This is not technicawwy an exampwe of "negative interest on excess reserves," because Sweden does not have a reserve reqwirement,[34] but imposing a reserve interest rate widout reserve reqwirements imposes an impwied reserve reqwirement of zero. The Riksbank studied de impact of dese changes and stated in a commentary report[35] dat dey wed to no disruptions in Swedish financiaw markets.

US Federaw Reserve cawwed a historic end to qwantitative easing in September 2017 and recentwy raised its benchmark short-term interest rate by a qwarter percentage point and signawed dat two more hikes are wikewy dis year. The decision moves de funds’ rate target to a range of 1.75% to 2%, from near zero in 2016.[36]

During de European debt crisis, government bonds of some countries (Switzerwand, Denmark, Germany, Finwand, de Nederwands and Austria) have been sowd at negative yiewds. Suggested expwanations incwude desire for safety and protection against de eurozone breaking up (in which case some eurozone countries might redenominate deir debt into a stronger currency).[37]

For practicaw purposes, investors and academics typicawwy view de yiewds on government or qwasi-government bonds guaranteed by a smaww number of de most creditwordy governments (UK, USA, Switzerwand, EU, Japan) to effectivewy have negwigibwe defauwt risk. As financiaw deory wouwd predict, investors and academics typicawwy do not view non-government guaranteed corporate bonds in de same way. Most credit anawysts vawue dem at a spread to simiwar government bonds wif simiwar duration, geographic exposure, and currency exposure. Through 2018 dere have onwy been a few of dese corporate bonds dat have traded at negative nominaw interest rates.
The most notabwe exampwe of dis was Nestwe, some of whose AAA-rated bonds traded at negative nominaw interest rate in 2015. However, some academics and investors bewieve dis may have been infwuenced by vowatiwity in de currency market during dis period.